144 0001789632 XXXXXXXX LIVE 0001786205 Arcellx, Inc. 001-41259 25 WEST WATKINS MILL ROAD SUITE A GAITHERSBURG MD 20878 240-723-6641 Heery Christopher Officer Common Morgan Stanley Smith Barney LLC Executive Services

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120000 5760000.00 48700000 12/18/2023 NASDAQ COMMON 12/18/2023 STOCK OPTION EXERCISE ISSUER N 120000 12/18/2023 COMPENSATION Y 12/18/2023 /s/ Christopher Heery